Call transmitter



March 4, 1947. w. GOFF 2,416,688

CALL TRANSMITTER I Filed May 10, 1944 s Sheets-Sheet 1 lNl ENTOR H. W GOFF ATTORNEY March 4, 1947. GOFF 2,416,688

CALL TRANSMITTER ATTORNEY March 4, 1947. w, GQFF 2,416,688

CALL TRANSMITTER Filed May 10, 1944 3 Sheets-Sheet 3 lNl/ENmR 81/ H. n GOFF ATTORNEY Patented Mar. 4, 1947 CALL'TRANSMITTER I Harold W. Gotf, Manhassct, N. Y., assign'or to Bell Telephone Laboratories, Incorporated, New V York, N. Y.,'a corporation of New York 1 Application May10, 1944, Serial No. 534,856

Claims. (01. 177-380) This invention relates to key-operated contact breaking devices for use, for example, for controlling the operation of selector and connector switches at a telephone exchange for establishing talking connections.

The object of this invention is the provision of a switching device of the type above referred to, which will be simple in construction, convenient for use, positive and accurate in operation.

A feature of the invention is the provision of a time mechanism actuated bya motor the tenslon of which is effected by the operation of .man-

ually operated keys under comparatively light I PIGSSHIG.

Av feature of the invention is the provision of means in the form of a common pivoted bar actuated by any key in a set of keys representing symbols, for simultaneously actuating elements of ratchet mechanisms for tensioning a motor spring. the function of which is to actuate a ratchet wheel and an escapement wheel forming parts of a time mechanism.

Another feature is the provision of means in the form of an anchor member in the time mechanism for imparting oscillatory movements to a balance wheel in response to the operation of the escapement wheel by the motor pring, the operation of the balance wheel successivelytensioning a spiral spring having one of its end portions disposed for engagement with the operable element of a pulsing contact for actuating the latter once for each complete oscillation of the balance wheel.

Another feature is the provision of stop elements movable by the operation of the keys for controlling the operation of one element in the ratchet mechanisms for determining the number of oscillations of the balance wheel in the time mechanism and thereby the operation of the pulsing contact.

Another feature is the provision of means defining a movable stop normally positioned for preventing the operation of the operable element of the pulsing contact during the ten-sioning of the spiral spring by a ratchet element actuated by the movement of a common bar, the operation of such means causing the operation of a latching mechanism by the movement of the escapeme'rlt wheel for permitting the operation of the contact upon the continued operation of the es-. capement wheel by the motor spring and theconsequent continued oscillations of the balance wheel.

Another feature is the provision of means actuated by the return movement of one of the ratchet elements in the form of a sector-shaped plate to normal non-operated position for actuating means for stopping the movement of the balance wheel simultaneously with the release of the operated key and the consequent reengagement of thestop means with the spiralspring for controlling the operation of the contact in relation to the symbol represented by the depressed key.

Another feature is the provision of means whereby the operation of any one of the key members is effective to cause the automatic operation of a latching bar to lock the non-operated key in that position while means is provided for latching the depressed key in the operated posi tion following the movement of the plate from normal to operated position. 7

Another feature of the invention is the provision of means in the form of a pivoted arm actuated by the return movementof the-de-,

pressed key to normal non-operated position for engaging means carried by'the balance wheel preparatory to the operation of the succeeding key for starting the operation of the balance wheel. Other novelfeature of the invention and ads vantages will appear from the following description and by the claims appended thereto, reference being had to the accompanying drawings in which: v 3

r Fig. 1 is an elevation view shown in perspective, the keys being shownin normal non-operated position; r Fig. 2 is a right side elevation view shown with a number of operating parts in sectors, the keys and the operating mechanism being shown in normal non-operated position;

Fig. 3 is a top view of Fig. .2 shown with the casing housing the mechanism removed and with the base with portions broken away.

Fig. 4 is a right side elevation view showing one of the keys and the operating mechanism in the operated position; I

Fig. 5 is a rear elevation view shown partially in section taken on line 5-5 of Fig. 4; and

Figs. 6 and 7 are detail views showing the con-' tact and elements of the time mechanism in different operated positions.

In the switching device of this invention. sometimes referred to as a call transmitter, abase i0 is provided for mounting the upright supports l1 and I 2 which are secured at their lower ends. to

the base as by a number of screws l3 and I4 best seen'in Fig. 3 and on the supports H and I2 is .l'qllinaled. a shaft l5 serving for pivotally'mount- OFFICE with the arm 24.

ing a set Of key members at Kl, K2, K3, K4, K5,

.K6, K1, K8, K9 and Kill having their free end portions extending through a common rectangularly-shaped opening l6 in an upright extending plate I! secured at its lower end to thebase II] as by a plurality of screws I8. The parallel portions a and b, Figs. 3 and 5 of plate. I! forming. the sides of :theopening l6 serve; to limitthe movement of the keys KI, K2, etc., from normal to operated position while retractile springs IIK; serve to return the keys KI, K2, K3, etc.,- to nor-' mal non-operated position, following each digit fectiv'e to'rotate a. sleeve l9 having one of its ends secured to one arm of U bar "Y nd on this s'leeveare' keyed the downwardly extending arms and 2|, the latter arm being provided at its free end with a pin 22serving for'hooking one end of a metallic belt 23, the other end of which issecured and wound around the hub of 'a'lever member 24 mounted for free rotation on a shaft 25 supported by the upright support I2 and support 26securedto'the base It by screws se and *4 tends in engageable relation with an operable stop in the form of ablock 48 mounted at the free end of a ribbon spring 49, the lower end of which is secured to an angle piece P in turn secured to the base l0.

The spiral spring 4'! as shown inFig. 6 at a point adjacent the end of its outer convolution is provided iwith a rectangularly-shaped slot through which the free end of an operable con- 10.

cessive tensioning of spiral spring 41 as effected tact spring 59 extends for operation by the sucby thejoscillation of the balance wheel 44 in a manner which will be hereinafter described in detail.

is held against rotation on thesesupports by pins 2 8 and 29 as shown in Figs. 3 and 5. According tothis construction the operation of any one of the key members KIQKZ, K3, etc., and c onse-.

the sleeve'l9 and to the arms 26 and 2| carried thereby for actuating the arm 24 through the metallicbelt 23 and thereby winding a spiral retractile spring 30 having its innerconvolution securedto shaft 25 and its outer convolution hooked to a pin 3| carried by a projection formed The arm 24 is provided at its free end portion with a spring pressed pawl 32 normally engaging witha tooth or projection 33'formed at the periphery of a sector-shaped plate'34 bestseen'in Figs. 2; 3 and 4 pivoted on shaft 25. This plate is provided with a projection 35formoun'ting a spring-pressed pawl 36 engaging a ratchet wheel 31 mounted for free rotation on the'shaft' 25' and actuated by the movement of sector plate 34un-j der the tension of a retractile spiral spring 38 having one of its ends secured to shaft 25 and its other end hooked to a pin'40 carried by the sec tor plate 34 so as to be tensioned by the angular movement of this plate as effected by arm 24 and integrally with the upright support 26. The anchor member 4| isprovided with the usual laterally extending pins P and PI for engaging with the teeth "of escapement wheel'39 and the forked arm of the anchor member 4| best seen in Figs. 2, 6 and 7 engages a'pin 46 carrie'dby the balance wheel 44 mounted for free. rotation on shaft 25.. A spiral. spring 41 has the end ofits inner convolution secured to the hub of balance wheel 44 and the end'pfits outer convolution 1;-

To the spiral spring 4'! is secured a block piece b engaging a stationary pin SP upon the rotation. of the balance wheel in the direction indi-' cated by the arrow so that a faster build-up of the tension of the spiral spring is obtained during the closing period of thepulsing contact,

To the freeend portion of arm 20 keyedon sleeve I9 is pivoted one end of a link bar 5|, the opposite end of which connects with an arm 52 best seen in Figs. 2 and 4 pivoted on shaft 25.

This arm is provided at its free end with a springpressed pawl 53 normally engaging with a ratchet tooth 54 formed at the periphery of balance wheel 44. This pawl is formed with an arm 53 disposed in engag'eable relation with a pin 56 laterally extending from an upright support 51 secured to the base l6, pin- 56 serving to disengage the pawl 53'from the balance wheel 44 following the operation of the latter by the operation of arm 23 and link bar 5| as effected by the movement of U-shaped' bar HY under control of any one of the keys KI,.K2,'K3, etc.

The link bar 5! is formed with a projection 58 normally 7 engaging a 1 hairpin-shaped spring member 59 having one of its ends secured to the underside of block 48 and the other end extending when spring 49 is flexed in engageable'relation with one of the teeth of anchor wheel 39 as shown in Figs. 2 and 3 where it is normally held by a pin 6!] engaged by a ratchet-shaped tooth projection 6| carriedby the spring 59, the fiex- 7 ing of the spring 49 as shown in Fig. 2 being 'ef-' fected under the tension of retractile s'pring62 connecting with the U-'-shaped bar HY.

To the'key members Kl, K2, K3, etc. are at tached one end" of piano wires as WI, W2, W3,

fitted for sliding movement in'guiding members in the form of tubing tul, W2, W3, tu4, tu5, m6, m1, tu8, tu9, and'tulfl having one'of their ends secured to a supporting bar 63 formed at one end with a lug L, Fig. 4, bent at right angles thereto and secured to the upright extending plate l1, while the opposite end of the bar 63 is secured to the top disposed end of an arcuated-shaped such engagement causing to move the pawl32 out of engagement from the tooth 33 of pivoted sector plate 34 for permitting the return movement of the latter by the tension of spring, 38 simultaneously with the initial movement :of

. p balance wheel 44 as efiected by the arm 52, pawl 53, linktl and the arm 30 movable with the -U bar HY, the pawl 32 reengaging the tooth 330i pivoted sector plate: 34 upon the return of the depressed key to normal non-operated position as wil1 be hereinafter described in detail.

'The sector-shaped plate is provided with a projectiont'l disposed in engageable relation with an arm 68 keyed onta shaft69 journaled in lugs Hi and ll formed with the upright extending plate H and in a bracket 12 best seen in Figs. 2 and 13 secured to the arcuated member 64 as by a screw 73. r V

The angular movement of shaft 59 asimparted by the'tensionof a retractile spring 14 following the movement of sector plate 36 in the direction indicated by the arrow in'Fig. 2 is eilective to move the pawl-shaped plate 15 secured to shaft 69 in the path of similar lugs 15 formed with the key members Kl, K2, K3, etc., for engaging and holding the depressed key in the operated position as shown in Fig. a while another pawl-shaped plate 11 pivoted on studs laterally extending from lugs 96 and ill formed with the upright extending plate I? is permitted to move by the tension of a retractile spring 18 in engagement with the underside of lugs 16 of the non-operated keys for locking them'in that position upon the release of an arm 79 formed with plate H by an extension ea: carried by the U-shaped bar HY upon the movement of the latter by any one of the keys from normal to operated position, the operated key being released upon the return of sector plate 34 to normal position following each digit transmitting operation, while the return of U-shaped bar llY to normal non-operated positioncauses the projection ea: carried thereby to reengage the arm 79 oiplate H for moving the latter in the position as shown in Fig. 2 and therebyunlocking the non-operated keys.

' The seotoreshaped plate 34, as shown in Figs. 2 and 3, is provided with a pin Bil disposed in engageable relation with an arm 8! keyed on a shaft 3? journaled at both ends in upright supports l2 and 26 and on this shaft is mounted a wedge-shaped arm .83 provided for engaging a stop as carried by the balance wheel 44 for stopping the movement of the latter upon the return movement of sector plate 34 to normal and the consequent operation of arm 68 and. pawl 15 by f normal, this bar as above described engaging the 5.

arm :9 of locking plate H for moving the latter out of the path of the key members KI, K2, K3, etc.,, preparatory to the operation of a succeeding key.

In a typical example of operation; the movement of any one of the key members as K5, for example, from the position shown in Fig. 2 to the position shown in Fig. 4, is effective to impart a corresponding angular movement to the U shaped bar NY and thereby to the arms 20 and 2| keyed on sleeve [9 against the tension of retractile spring 62. The movement of arm .21 through the belt 23 is .efiective to impart .an angular movement to arm 24 on shaft '25 against the tension of its retractile spring 39 while the movement of 24 through the engagement of pawl 32 carried by the arm .withprojection 33 carried by the pivoted sector-shaped plate 34 rotates the latter to the point wherein the projection 86 formed with the pawl 32 ens-ages the 6 piano wire W5 which has been moved in its guiding tube tu5 across the groove do in the arcuated support 64 by the operation of key K5 :for re leasingthe sector plate 3 4. Themovement of this plate 34 as effected by the arm 024i iscefifective to tension the spring 38, the. function; of which is to return the plate 34. to. normal nonoperated position for actuating the time mechanism in a manner whichwill be hereinafter (le scribed in detail. l

The operation of arm 20 and that of link bar 5! which occurs simultaneously. with the operation of arm 24 by belt 23 is effective to impart a clockwise angular movement to the balance wheeled through the engagementof pawl 53 carried by arm 52 with the ratchet tooth portion 54 on the balance wheel to the point wherein the projection 55' formed with pawl 53 engages the pin 55 for releasing the balance wheel 44. The

movement of the balance wheel by pawl 53 is effective to engage the block b with the stationary pin SP to cause the-tension built up of spiral spring 41, The movement of link bar 5| and the wheel 44 and. therefore the successive tensioning of the spiral spring 4.! and thereby the operation of contact spring 53. It is to be noted, however, 1

that due to the end of spiral spring 41 resting against the block as, the initial movement of the balance wheel M as imparted by the pawl 53 and the consequent tensioning of spring 4'5, this contact spring is not operated until the tooth 5| formed at the end of spring 59 is disengaged from the'pin it by, the rotation of escapement Wheel 3950 as to permit the movement of block 48 away from the end of sprial spring 4'! and thereby the free movement of spiral spring M in phase with.

the oscillation of balance wheel Ml for operating the contact it once for each counter-clockwise oscillation period of the balance wheel for transmitting as for example above-mentioned five pulses when the sector-shaped plate 34 reaches its normal non-operated position following the operation of arm 58 of latch bar .75 for releasin the operated key and the engagement of, pin with arm 81 to move the wedge 83 in engagement with the projection 34 carried by balance wheel as for stopping the operation of the latter and the engagement of the pawl 32 with the projection 33 of the plate 34 which defines the normal non.- operated position of the plate.

The operation of arm 68 and the consequent return movement of the operated key to normal non-operated position by the tension of its retractile spring 11X isiollowed by the returnmovement of the U-shaped bar |7Y under the tension of retractile spring .62 and the return movement of arms 26 and-21.. The movement of army 29 to normal position as shown in Fig .2 permits the reensagcment of tooth 61 formed with spring .59 with the pin 50 simultaneously with the movement of block 48 in the path of spiral spring 41 and the engagement of the end of spring 59 in one of the teeth of escapement wheel 39 while the movement of arm Zlpermits the return movement of arm 24 under the tensicn or its retractile spring :30 to a wherein th'eLarmt-S of pawl 32" engages the lug 1m formed with the arouated supporting member 64 to cause this pawlto reengage the portion 33. of sector plate '34 and the transmitter mechanism isnow ready for the operation of a successive k y. -1The'time mechanism above described which determinesithe intervals betwen pulses requires a low tension motor spring and therefore low pressure onthe manually operable keys in comparison to call transmitters of the type using centrifugal governors requiring high friction coeflicient', high tension on the motor spring and thereof high pressure on 16 key members for proper operation of the pulsing mechanisms.

'What is claimed is: v 1. Ina switching device'; a contact, a time'mechanism having an escapement'wheel, an anchor member, a balance wheel and a spiral spring, a

' individually for tensioning said spiral spring and means operable for starting and stopping the operation of said balance wheel for controlling the number of make and break of said contact according to the operated key member in said set.

2.'In"aswitching device, a time mechanism having an escapement wheel, a balance wheel and a spiral spring, a plurality of key members manually operable individually for tensioning said 'spiralspring for actuating said escapement Wheel to'cause the operation of said-balance wheel and the successive tensioning of said spiral spring, and a contact actuated by the successive tensioning of said spiral spring by the movement of said balance wheel.

3. In a make and break contacting device, a time mechanism, said mechanism comprising an escapement wheel, an anchor, a balance wheel and a spiral spring, a contact disposed in engageable relation with the end of the outer convolution of said spiral spring, a motor spring, manually operable means for tensioning said motor spring for actuating said mechanism, and a mechanism operable by'the tension of said motor .spring for engaging means carried by said balance wheel for controlling the operation of said contact by said spiral spring.

4. In a call transmitter, a set of key members, a pivoted U-shaped bar operable by the opera,- tion of any one of said key members, a time mechanism having an escapement wheel, an anchor engaging said wheel, a balance wheel and a spiral spring, a ratchet mechanism, having a spring tensioned by the movement of said bar for actuating said time mechanism, and a pulsing contact actuated by said spiral spring upon the operation of said balance wheel.

5. In a call transmitter, a pulsing contact, a set of key members, a U-shaped bar disposed for operation by the movement of any one of said her actuated by said escapement wheel, aibalance wheel actuated by said anchor members and a spiral spring successively tensioned by the movement of said escapement wheel for actuating said a pivoted lever member actuated by the operation of said bar, saidlever member having a pawl, a plate having aratchet tooth element engaged by said pawl and operable for tensioning said motor spring, means positioned in thepath of said pawl by the movement of the operated key for disengaging said pawl from said element carried by said plate for actuating said time mechanism in its return movement to normal positionfor operating said contact a number of times corresponding to the digit of the operated key.

7. In a call transmitter mechanism, a set of key members, a U-shaped bar disposed for operation by the movement of any one of said key members, a time mechanism comprising an escapementwheel, an anchor, a balance wheel and a'spiral spring, a motor spring tensioned by the operation of said U bar for actuating said mechanism, and a pulsing contact acuated upon the successive tensioning of said spiral spring by the operation of said balance Wheel.

8. In a call transmitter, a pulsing contact, a set of key members, a U-shaped bar disposed for operation by the movement of any one of said key members, means operable upon the opera tion of any one of saidkey members for latching the non-operated keys in that position, a

time mechanism, a sector-shaped plate actuated in one direction by the movement of saidbar, a motor spring tensioned by the movement of said plate for actuating the latter in the reverse dif ating the last-mentioned latching means upon its return movement to normal non-operated posi- I tion by the tension of said motor spring for releasing the operated key following the operation of said contact.

key members, a commo'n shaft for pivoting said shapedplate pivoted on the last-mentioned shaft,

9. spring-pressed pawl carried by saidlever member, engaging means carried by said plate for rotating it, an escapement wheel, a motor spring tensioned by the movement of said plate for actuating said escapement wheel, an anchor mem- 9. In'a call transmitter, a set of key members, a U-shaped bar disposed for operation by the individual movement of each of said key members, an arm actuated by the movement of said bar, a shaft, a lever member mounted for free rotation on said shaft, means operatively connecting said arm to said lever member for actuating the latter, a sector-shaped plate mounted for free rotation on said shaft, a pawl carried by said lever member engaging means carried by saidplate for rotating it upon' the movement of said lever member, a time mechanism actuated by the movement of said plate, said mechanism comprising a ratchet wheel, a pawl carried by said plate engaging said ratchet wheel, anescapement wheel rotated by said ratchet Wheel, an anchor member actuated by said escapement wheel, a balance wheel and a spiral spring actuated by said anchor member having one of its ends connected to ,said balance wheel, a block member normally disposed in the path of the other end of said spring to cause the latter to; tension upon the oscillation of said balance wheel, another arm actuated by the operation of said bar, another lever member mounted for free rotation on said shaft, a link bar operatively connecting said other lever member to said other arm, a pawl carried by the last-mentioned arm, a ratchet tooth formed with said balance wheel normally engaged by the last-mentioned pawl for imparting the first oscillation to said balance wheel for tensioning said spiral spring, a contact disposed in operative relation with said spiral spring, and means operable upon the operation of said link bar for moving said block from the path of said spiral spring to cause the operation of said contact upon the continued operation of said balance wheel during the return movement of said sector-shaped plate, and a motor spring for effecting return movement of said plate.

10. In a call transmitter, a set of key members representing symbols, a bar disposed for operation by the individual movement of said key members, a shaft, a time mechanism having an escapement wheel and a balance wheel mounted on said shaft, a motor spring for actuating said mechanism, piano wires secured to said key 25 Number members, a guiding element for each of said wires, an arcuated support having means for securely receiving one end of each of said guiding elements in equal spaced relation to each other, a sector-shaped platemounted on said shaft having a clutch element, a lever member mounted on said shaft having a clutch element normally engaging the first-mentioned clutch element for rotating said plate for tensioning said motor spring, the clutch element carried by said plate operating upon its engagement with the wire actuated by one of said key members for controlling the operation of said escapement Wheel and said balance wheel according to the symbol represented by the operation of one of said key members, a spiral spring in said time mechanism, and a contact actuated by said spiral spring.

HAROLD W. GOFF.

REFERENCES CITED The following references are of record in the Name Date 1,672,791 Thimblethorpe June 5, 1928 2,329,234 Willis Sept. 14, 1943 

